1. Field of the Invention
The present invention relates to a portable information terminal which also functions as a mobile communication terminal, and to a portable information terminal which can be connected to a mobile communication terminal.
2. Description of the Related Art
A mobile communication terminal, such as a portable telephone and a radio data communication terminal, accesses a plurality of base stations of a certain communication system to which an access is permitted, receives access information, such as an identification number which is assigned to an accessed base station, the type of a communication service company, a field intensity and propagation conditions of bit error rate and the like, from the accessed base station which responds to the access, and holds the access information while communicating through the accessed base station.
Various mobile communication systems have been adopted in various countries and have been each standardized, such as PHS, TACS and PDC for portable telephones in Japan, AMPS which serves as standards for analog cellular phones in North America, CDPD, RAM and Ardis which serve as standards for mobile data communication in North America, and GSM which serves as standards for digital cellular phones in Europe.
Further, for each system, necessary access information, such as identification numbers of a base station and a terminal, identification information of a communication service company, a field intensity and a bit error rate, is defined which is needed for accessing each communication system. For example, for base stations which are currently accessed, there are system ID (SID) which is used in the AMPS method, cell ID (CellID) which is used in the CDPD method, etc.
In addition to a clock function, a calendar function and the like, a portable information terminal has functions of inputting, holding, displaying, searching and correcting various information. The various information includes general information, such as a schedule, an action list, a dictionary and a memory, and additionally specific information.
The specific information is classified into three types, i.e., information dependent upon regions, information dependent upon communication service companies, and information dependent upon both regions and communication service companies. Examples of specific information which is dependent upon regions are addresses of entities, such as a tourist information bureau, a public organization and a branch office of an enterprise, which are located in a certain city, or the contents of major events of the city. Such items regarding each city are stored in one table. Alternatively, examples are a currency, a climate condition, holidays, addresses of embassy buildings and the like of a country, and these items regarding each city are stored in one table. Further, a local time is of the same kind. Local times of various countries or cities are stored in one table. This information is extremely important for the United States of America where there are a number of time zones, and for Southeast Asia and Europe where there are a number of countries next to each other.
Examples of specific information which is dependent upon communication service companies are telephone numbers for customer support which is available from each communication service company which are related to a telephone function, and a network address of a host server of each communication service company and telephone numbers of access points which are related to a data communication function. These pieces of information are stored in one table, for each communication service company.
Examples of specific information which is dependent upon both regions and communication service companies are telephone numbers for customer services, such as a traffic information service, a weather forecast service and a tourist information service, for each region which are uniquely available from each communication service company, or telephone numbers for reaching the police, an emergency medical service, a fire department and the like. These pieces of information are stored in one table, for each region and each communication service company.
Among such a portable information terminal, a portable information terminal which has a mobile communication function to also serve as a mobile communication terminal and a portable information terminal which can be used as it is connected to a mobile communication terminal have been proposed.
When a user obtains specific information through a portable information terminal, he must select one table which stores the desired specific information out of a plurality of tables which store specific information. To this end, the user himself must search the respective tables or enter a predetermined input (e.g., data such as a region and a communication service company). The former case takes a considerable amount of time for the very search process, whereas the latter case requires the user to recognize data to enter. Thus, the user cannot treat information efficiently, and an operation is complex.
Further, as the user is required to select a table, it is possible that the user selects a table which stores wrong specific information (which is not the desired specific information) because of some reason (e.g., a wrong enter) and consequently obtains the wrong specific information. Among the specific information, those which are related to communication, such as telephone numbers, in particular, are difficult to judge if the obtained information is the desired information. Hence, the user may execute unnecessary communication using the wrong information, which results in a wasteful communication cost.
As a portable information terminal which has a function to serve as a mobile communication terminal, such a portable information terminal has been proposed whose function as a mobile communication terminal is realized by a plurality of different communication systems rather than by only one communication system. With such a portable information terminal, a user can switch communication systems for communication.
However, to this end, the user must judge which communication system is most appropriate. This is difficult since whether subscription is required, a charging system, the types of services are different among different communication systems. There can be a problem that as a result of switching communication systems, a communication cost becomes expensive for wasteful communication or the quality of communication degrades.